Vitamin B2 ( riboflavin )

Vitamin B2 ( Riboflavin ) is needed by the body to form two substances that are vital for turning the calories from protein, fat, and carbohydrate in food into a form that cells can use efficiently: FAD -which stands for flavin adenine dinucleotide; and FMN - which stands for flavin mononucleotide. (A lack of riboflavin in the body reduces energy levels.) Riboflavin is also needed for the formation of hair, skin, and nails.

Riboflavin deficiency has profound effects on the metabolism of carbohydrates, fats, and protein. All three of these basic food elements require riboflavin if they are to be properly utilized by the body. When not enough riboflavin is supplied, carbohydrate utilization decreases, so the body "tells" itself to consume more carbohydrates to make up for the diminished efficiency.

When the vitamin is undersupplied, protein utilization also drops off. More protein is excreted in the urine. This begins a vicious cycle, because when more protein has to be excreted, the increased urinary output will also eliminate more riboflavin from the body.

Dietary fat also increases the body's need for riboflavin. When insufficient riboflavin is supplied to handle the fat in the diet, the fat is deposited in the liver, kidneys, adrenals, and arterial walls.

Riboflavin deficiency also interferes with the activity of the thyroid gland, and produces birth defects which affect the nervous system, skin, skeleton, and vascular system. In young animals, riboflavin deficiency diminishes learning capacity. Such effects apparently linger, because supplying adequate riboflavin when the animals are older does not restore normal learning.

A person whose riboflavin demands exceed the supply may have an inflamed tongue, lips, or mouth. The eyes can become oversensitive to light and will itch, burn, and appear bloodshot and teary. Seborrheic (greasy scaling) dermatitis will afflict the area around the lips and nose, eyes, behind the ears, and scrotum. Any of these symptoms can be caused by many other factors. However, if they all appear together and a person's diet is suspect, the finger of suspicion points to riboflavin deficiency.

The changes that occur in the eyes may be especially important. Riboflavin deficiency produces opacities in the eyes of animals identical to those caused by cataracts. Corneal opacity has also been found in people with riboflavin deficiency. And when doctors tested twenty-two people with cataracts, they found that eight of them had cellular deficiencies of riboflavin.

Riboflavin deficiency can produce psychiatric disturbances, too. In one riboflavin-deficiency study, six young men were maintained on a riboflavin-deficient diet-under twenty-four-hour medical supervision-and given batteries of psychological tests. Significant psychological changes took place as the deficiencies took hold. The men felt more lethargic and depressed. They complained more about pains and illnesses they didn't have (hypochondriasis). They scored higher on hysteria and psychopathic-deviate scales, and underwent measurable personality shifts. Interestingly, none of the "classic" symptoms of riboflavin deficiency (dermatitis, inflammation of the eyes, etc.) appeared before the experiment ended. And when the men were given riboflavin at the end of the experiment-some two months or more after it began-it took more than two weeks for all of the psychiatric symptoms to disappear.

In another study of the psychological effects of vitamins, researchers associated high blood levels of riboflavin with increased extroversion, concentration, and contentment.

Riboflavin may have a beneficial effect upon the muscles' ability to perform. Giving young athletes a moderate riboflavin supplement has been reported to increase their resistance to fatigue by about eleven percent. In a separate experiment, young athletes were given ten mg. of riboflavin, and their neuromuscular irritability-a biochemical measurement associated with fatigue-was lowered. Eight of the athletes were deficient in riboflavin, however, before the supplementation. This not only suggests an increased need for riboflavin during training and exercise, but also that a riboflavin supplement might be a good idea for athletes. Especially athletes who have to perform in the cold, since animal experiments have demonstrated that riboflavin in high doses enabled rats to swim for longer periods in cold water.

Riboflavin apparently helps protect the body by maintaining the immune response and by detoxifying noxious chemicals that enter the body. Cellular antibody production and activity is diminished in riboflavin deficiency.  Riboflavin also helps the liver detoxify chemicals such as estrogens, carcinogens, and other harmful natural and synthetic chemicals.  The discovery that boric acid poisoning causes excessive levels of riboflavin in the urine led doctors to speculate that the vitamin may be involved in detoxifying the common poison.

Riboflavin detoxifies cancer-causing chemicals. In one experiment, riboflavin prevented the formation of liver tumors in rats treated with such chemicals. Riboflavin deficiency has been shown to stimulate growth of tumors. Less riboflavin than normal is excreted in cases of cancer of the stomach, breast, uterus, skin, and lung-an indication of increased utilization and need. In one study of 1000 adults with cancer, virtually no riboflavin was excreted by eighty percent of the people, regardless of where the tumor was.

Research shows that active people need far more than the RDA of riboflavin. In one study the diet of women who jogged twenty-five to fifty minutes per day was controlled to include measurable amounts of riboflavin. Then, as the levels of the vitamin were varied, the women's blood was tested for the vitamin. It took a dietary intake of riboflavin of at least double the RDA to raise their blood levels to what doctors considered an acceptable range. In a similar study, it was revealed that not only does exercise increase the body's usage of and requirements for riboflavin, but a weight loss diet does, too.

Where is it found ?

The richest natural sources of riboflavin include organ meats, fish, dairy products, eggs, green leafy vegetables, wheat germ, whole grains, and legumes. Riboflavin is not destroyed by heat, but soaking foods or cooking them in water for long periods of time can result in substantial losses, since the vitamin is water-soluble. Exposure to light will also destroy riboflavin. Riboflavin is available in a wide range of supplementary dosages, from less than one mg. to hundreds of milligrams. Riboflavin is not toxic. Attempts to produce toxic reactions in experimental animals have failed. Taking riboflavin along with food or fiber increases absorption of the vitamin.

Who is likely to be deficient ?

Vitamin B2 deficiency can occur in alcoholics. Also, a deficiency may be more likely in people with cataracts or sickle cell anemia.

How much to take

The RDA for riboflavin varies according to weight, metabolic rate, growth, and caloric intake, and ranges from .4 mg. for infants to 1.9 mg. for lactating women, with male adults requiring 1.7 mg. and female adults 1.2 mg. Remember, the RDA is an arbitrary figure and does not necessarily bear any relation to what an individual's needs really might be. Some researchers recommend higher dietary amounts, with supplementation during periods of stress or exertion.

Side effects

At supplemental and dietary levels, vitamin B2 is nontoxic.

Vitamin B2 works with vitamins B1, B3, and B6; consequently, vitamin B2 should be taken as part of a B complex supplement.

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